Effect of protein degradability on urea nitrogen in sheep milk [animal feeding - Liguria]
1998
Ubertalle, A. | Fortina, R. | Battaglini, L.M. | Mimosi, A. | Profitti, M. (Turin Univ. (Italy). Dipartimento di Scienze Zootecniche)
A milk production trial with Delle Langhe sheep was conducted to test the animal response to the varying levels of dietary protein degradation and solubility in the rumen. Fifteen ewes in mid lactation were used in a latin square model design. Isocaloric and isonitrogenous rations, containing a ratio of 50:50 forage to concentrate, were formulated using whole roasted soybean (Diet A), soybean meal 44 (Diet B), and soybean meal 44 + whole roasted soybean (Diet C, control). Milk yield was measured daily and milk samples were analyzed for fat, protein, lactose, casein, urea rennetting ability. Milk yield, protein, fat and lactose were not influenced by diet, while signficant differences for urea (P0.01) were observed when the soybean 44 of diet C was replaced by whole soybean (diet C vs. diet A: 44.87 mg/dl vs. 39.96 mf/dl). Rennetting ability did not show differences among diets and was not correlated to milk urea values. Baseline values for milk urea in Delle Langhe sheep milk ranged between 40 mg/dl and 45 mg/dl and resulted higher than in dairy cows, but no influences were observed on milk yield and quality
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